Does Leptinotarsa decemlineata larval survival after pesticide treatment depend on microbiome composition?

Abstract

BackgroundThe microbiomes of some arthropods are believed to eliminate pesticides by chemical degradation or stimulation of the host immune system. The Colorado potato beetle (CPB; Leptinotarsa decemlineata) is an important agricultural pest with known resistance to used pesticides. We sought to analyze microbiome composition in CPB larvae from different sites and to identify the effect of pesticides on the microbiome of surviving and dead larvae after chlorpyrifos treatment in laboratory. Changes in Lactococcus lactis community in larvae treated with chlorpyrifos and fed by potato leaves with L. lactis cover were studied in manipulative experiment. The microbiome was characterized by sequencing the 16S RNA gene.ResultsThe microbiome of L. decemlineata larvae is composed of a few operational taxonomic units (OTUs) (Enterobacteriaceae, Pseudocitrobacter, Acinetobacter, Pseudomonas, L. lactis, Enterococcus, Burkholderia, and Spiroplasma leptinotarsae). The microbiome varied among the samples from eight sites and showed differences in profiles between surviving and dead larvae. The survival of larvae after chlorpyrifos treatment was correlated with a higher proportion of L. lactis sequences in the microbiome. The S. leptinotarsa profile also increased in the survived larvae, but this OTU was not present in all sampling sites. In manipulative experiments, larvae treated with L. lactis had 5‐fold lower mortality rates than untreated larvae.ConclusionThese results indicate that the microbiome of larvae is formed from a few bacterial taxa depending on the sampling site. A member of the gut microbiome, L. lactis, is believed to help overcome the toxic effects of chlorpyrifos in the larval gut.This article is protected by copyright. All rights reserved.

Cereal leaf beetle‐associated bacteria enhance the survival of their host upon insecticide treatments and respond differently to insecticides with different modes of action

“…Insect‐associated microbes are able to utilize insecticides as a sole source of carbon and energy (Jaffar et al, 2022 ), but the ability to degrade insecticides depends, among others, on the temperature, pH, nutrients availability, structure of a bacterial community or class of the insecticide (Gomes et al, 2020 ). It was recorded that bacteria might detoxify multiple insecticide classes including pyrethroids, neonicotinoids, organophosphates (Blanton & Peterson, 2020 ; Stara & Hubert, 2023 ). For instance, Burkholderia mallei , Stenotrophomonas maltophilia or Citrobacter amalonaticus can enhance the host's metabolism of insecticides (Wang et al, 2022 ).…”

“…Chlorpyrifos is an organophosphate pesticide, that is an inhibitor of acetylcholinesterase, that causes acute neurotoxicity. Chlorpyrifos is one of the most widely used pesticides worldwide, except in the European Union, where its use was banned in 2020 (Stara & Hubert, 2023 ). In turn, flonicamid, is a pyridinecarboxamide (Zhao, Wang, et al, 2021 ), that disrupts insect chordotonal organs, but the specific target site of the chemical is unknown (Spalthoff et al, 2022 ).…”